DOCSLIB.ORG

Report on the Clearing Trial of Pteronia Incana (Bluebush)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Report on the Clearing Trial of Pteronia Incana (Bluebush) Feature Report on the clearing trial of Pteronia incana (bluebush) and Elytroppappus rhinocerotis (renosterbos) in Mgwalana catchment, Ngqushwa District, Eastern Cape Province: rehabilitating degraded rangeland AR PALMER Agricultural Research Council, Animal Production Institute E mail: [email protected] Introduction control measure. In order to evaluate the effective- nvasion of blue bush ( Pteronia incana ) and renos- ness and cost of clearing these species, a project Iterbos ( Elytropappus rhinocerotis ) continues in was initiated to experimentally clear a number of trial the rangeland of the Mgwalana catchment of the areas as part of the National Department of Agri- Ngqushwa district (formerly Peddie) of the Eastern culture’s Landcare Programme. Five sites of known Cape (Kakembo et al. 2006, Kakembo et al. 2007). bluebush and renosterbos infestation were identified These species, both indigenous to the Nama karoo from high resolution near infra-red (NIR) photography region of South Africa, successfully invade natural in the Mgwalana catchment. In four sites, intensive grassland and thicket. Both species have been re- manual clearing was carried out to assess the cost corded in un-disturbed rangelands across the Great and efficacy of three clearing techniques. At the fifth Fish river and Keiskamma river valleys, but are known site, a landscape-scale clearing action occurred to to increase and become dominant in the absence of measure the impact of clearing on the MODIS leaf fire or when excessive soil disturbance has occurred. area index (LAI). The sites varied in the density of Disturbance of the soil surface by excessive tram- infestation. pling, cultivation (Kakembo 2001) or subterranean mammal activity (e.g. termites or mole rats) creates Aim gaps which can be colonized by seedlings. The aim of this trial was to evaluate the cost and effectiveness of manual clearing of blue bush (laven- Control of both species on free-hold rangeland der bush) ( Pteronia incana ) and renosterbos ( Elytro- with adequate infra-structure can be affected using pappus rhinocerotis ) on the communal rangelands of fire. However, communal rangelands do not lend the Ngqushwa district. themselves to the use of fire, as there are no options for the control of grazing after burning, and little op- Methods portunity to build up fuel loads which would enable Three physical clearing treatments were applied at a burn to be applied. This is principally due to the each of the intensive clearing site in March 2003. absence of livestock control systems (adequately Treatments were applied to three randomly selected fenced and gated camps, water provision) in areas sub-plots of the five quadrangular sub-plots of ap- under communal tenure. The project aims at evaluat- proximately 3ha. (100mx300m). One sub-plot was ing the cost effectiveness of a range of manual clear- used as a control, and the fifth was used as the ing techniques which may be used as an alternative area to be packed with dead material and burned 22 GRASSROOTS | The GRASSLAND SOCIETY of SOUTHERN AFRICA | www.grassland.org.za August 2010 | Vol 10 No.3 Feature at a later stage. A burn was applied to these sites on 17 September 2003. The three physical clearing treatments were applied during a single operation in March 2003. The first used a specially designed instrument or “dicker” (manufactured by Fabcomp, King Williams Town), which pulls the rooted plant out of the ground. The second used commercial lopping shears to cut the plant off at the base, and the third employed a “slasher” to chop the plant off. At all sites, the density of large plants (>0.5m in height), was determined using the point-centred quarter (PCQ) technique. The boundaries of each treatment were determined from the aerial photo- graphs, and marked in the field using a GPS. Each team was allocated an equal amount of cash to com- plete the three treatments and pack the burn plot. The limiting factor to completing the 3 ha was the fi- nances allocated to each team. Teams were encour- aged to complete the full 3ha, but at the highest den- sities of infestation this was not possible within the financial allocation. At the completion of the 22 day working period, the area completed by each team was recorded using a GPS and the area calculated using a GIS package. MODIS LAI product (Collection 4) We acquired 8 years of the MODIS 8-day 1 km Col- lection 4 (MOD15A2) composite LAI/FPAR product (Knyazikhin et al . 1998) for the period March 2000 to Photo: Tony Palmer. The dicker instrument being operated by December 2007 from the NASA Distributed Active one of the ladies from the village of Nyaniso, Archive Centre. The data were extracted from the archive using the MODIS re-projection tool (HegTool) and imported into IDRISI (Version I32.11, Clark Labs) image processing package to create an 8-year data stack. The geo-codes for the centre of site 5 and the two control sites (village, un-cleared and grassland) were entered into the GIS and 8-day LAI values for each site were extracted. August 2010 | Vol 10 No.3 www.grassland.org.za | The GRASSLAND SOCIETY of SOUTHERN AFRICA | GRASSROOTS 23 Feature Rehabilitating Degraded Rangeland Results The results of the costs associated with the various treatments are presented (Table 1). Total person Treatment Site 1 Density Team Celetyuma days days Team Area (ha) worked Area/day size Cost per ha. Dicker 1.99441 High 38 0.052484 3 114 R 2,958.86 Lopper 2.359212 Low 7 0.33703 3 21 R 460.77 Slasher 2.971566 Low 6 0.495261 3 18 R 313.56 Pack 1.944959 17 0.114409 1 17 R 452.45 Control 3 Total 170 R 51.76 Site 2 Team Mgwalana days Team Area (ha) worked Area/day size Cost per ha. Dicker 0.985735 High 18 0.054763 3 54 R 2,398.39 Lopper 0.716058 High 21 0.034098 3 63 R 3,851.93 Slasher 0.78571 High 21 0.037415 3 63 R 3,510.47 Pack 0.135282 21 0.006442 1 21 R 6,796.21 Control 0.764488 Total 201 R 43.78 Team Site 3 Mgwalana:Youth days Team Area (ha) worked Area/day size Cost per ha. Dicker 0.322315 High 22 0.014651 3 66 R 8,190.74 Lopper 0.547779 High 22 0.024899 3 66 R 4,819.46 Slasher 0.649184 High 22 0.029508 3 66 R 4,066.65 Pack 0.62375 22 0.028352 1 22 R 1,410.82 Control 0.759029 Total 220 R 40.00 Site 4 Team:Amahlubi days Team Area (ha) worked Area/day size Cost per ha. Dicker 2.429 Moderate 11 0.220818 3 33 R 934.03 Lopper 2.409477 Moderate 14 0.172105 3 42 R 1,198.39 Slasher 2.870326 Moderate 13 0.220794 3 39 R 934.13 Pack 0.52434 14 0.037453 1 14 R 1,835.64 Control 2.575065 Total 128 R 68.75 24 GRASSROOTS | The GRASSLAND SOCIETY of SOUTHERN AFRICA | www.grassland.org.za August 2010 | Vol 10 No.3 Feature Near infra-red imagery was recorded in October 2004 over 2 sites using the Kodak DCS420 infra- red digital camera. Eighteen months after clearing (October 2004) there were some visible differences in the near infra red reflectance and NDVI’s (Figure 1) between treatments, but these were not all signifi- cant and their interpretation must be dealt with cau- tiously. The dicker treatment on Site 3 had a higher infra-red signal and NDVI than the other treatments (Figure 1). Mean Plot (Spreadsheet2 10v*44c) 0.20 0.18 0.16 0.14 0.12 0.10 0.08 NDVI_2004 0.06 0.04 0.02 0.00 -0.02 -0.04 Mean 1 2 3 4 5 6 7 Mean±0.95*SE Treatment Figure 1. NDVI values for the 4 treatments, control, adjacent woody thicket and good condition grassland in October 2004. NDVI was calculated from the NIR and red bands of the Kodak DCS420 digital camera. 1=Dicker, 2=Control, 3=Lopper, 4=Slasher, 5=Burned (Falkia repens absent)/ bare soil, 6=Riparian thicket (woody species), 7=Good grassland, un-invaded by Pteronia incana. This pattern was not repeated at site 2. This may be due to the stimulation of the soil microbial activ- ity after complete extraction of plants by the dicker, resulting in the release of nutrients and greater active green growth. During October 2004, these burn scars were covered by a single herbaceous species, Falkia repens. This was not a desirable species, and as there was only one herbaceous species present, this was likely to die off during the dry season, leaving no ground cover. The NDVI of woody shrubs and healthy grassland were significantly higher than Pteronia incana stands and clearing treatments (Figure 2). August 2010 | Vol 10 No.3 www.grassland.org.za | The GRASSLAND SOCIETY of SOUTHERN AFRICA | GRASSROOTS 25 Feature Rehabilitating Degraded Rangeland Mean Plot NDVI_2001 0.12 0.10 0.08 0.06 0.04 0.02 0.00 NDVI -0.02 -0.04 -0.06 -0.08 -0.10 -0.12 -0.14 Mean 1 2 3 4 5 Mean±0.95*SE Treatment Figure 2. The mean and standard errors of the DCS 420 NDVI’s for the five treatments. The riparian zone (Treatment 4), with its woody component and high perennial grass cover has the highest NDVI, followed by the control grassland in good condition (Treatment 2). 1= sparse grassland with Pteronia incana, 2=grassland with Elytropappas rhinocoerotis (control), 3=Pteronia incana shrubland, 4=riparian thicket, 5=sparse shrubland on shallow rocky soil.
Load more

Recommended publications
  • Artemisia Afra: a Potential Flagship for African Medicinal Plants? ⁎ N.Q
    Available online at www.sciencedirect.com South African Journal of Botany 75 (2009) 185–195 www.elsevier.com/locate/sajb Review Artemisia afra: A potential flagship for African medicinal plants? ⁎ N.Q. Liu, F. Van der Kooy , R. Verpoorte Division of Pharmacognosy, Section of Metabolomics, Institute of Biology, Leiden University, PO Box 9502, 2300RA Leiden, The Netherlands Received 11 July 2008; received in revised form 4 November 2008; accepted 6 November 2008 Abstract The genus Artemisia consists of about 500 species, occurring throughout the world. Some very important drug leads have been discovered from this genus, notably artemisinin, the well known anti-malarial drug isolated from the Chinese herb Artemisia annua. The genus is also known for its aromatic nature and hence research has been focussed on the chemical compositions of the volatile secondary metabolites obtained from various Artemisia species. In the southern African region, A. afra is one of the most popular and commonly used herbal medicines. It is used to treat various ailments ranging from coughs and colds to malaria and diabetes. Although it is one of the most popular local herbal medicines, only limited scientific research, mainly focussing on the volatile secondary metabolites content, has been conducted on this species. The aim of this review was therefore to collect all available scientific literature published on A. afra and combine it into this paper. In this review, a general overview will be given on the morphology, taxonomy and geographical distribution of A. afra. The major focus will however be on the secondary metabolites, mainly the volatile secondary metabolites, which have been identified from this species.
    [Show full text]
  • Asteraceae | Plantz Africa About:Reader?Url=
    Asteraceae | Plantz Africa about:reader?url=http://pza.sanbi.org/asteraceae pza.sanbi.org Asteraceae | Plantz Africa Introduction This is probably the largest family of flowering plants, with more than 25 000 species world-wide, growing from sea-level to the highest mountain peaks. It is absent only from Antarctica. In southern Africa it is also one of the biggest families of flowering plants with about 246 genera and 2 300 species. Many of the species have economic value. They show remarkable variation in growth form and general morphology because they occur in so many different localities and habitats. Description Description Almost all the features generally occurring in plants, can be found in this family! There are annual, biennial or perennial herbs, dwarf shrubs, shrubs, a few trees, some scramblers and aquatics. Some are succulent, whereas while others are spiny and some have milky sap. Many perennial species are adapted to survive the cold, dry winter season of the highveld by underground storage organs and producing annual stems in spring. The leaves can be arranged alternately, opposite or whorled along the stem; sometimes they are situated at the base of the stem (radical and rosulate) or in groups. Some have a petiole while others are sessile. The leaves can be simple with smooth margins or the margins can be toothed, lobed or variously dissected to such an extent that the leaves are actually compound with numerous leaf segments. Many species in the karroo and fynbos vegetation have small, needle-like leaves to survive the hot, dry summer seasons. These leaves look almost like the leaves of the genus Erica , and are called ericoid.
    [Show full text]
  • Pteronia Camphorata) Page 1 of 9
    Research Article Medicinal use and identity of ǀnhora (Pteronia camphorata) Page 1 of 9 San and Nama indigenous knowledge: The case of AUTHORS: nhora (Pteronia camphorata) and its medicinal use Isabel M. Hulley1 ǀ Patricia M. Tilney1 Sandy F. Van Vuuren2 A hitherto unidentified medicinal plant is here identified for the first time as Pteronia camphorata (L.) L., Guy P.P. Kamatou3 an aromatic shrub of the Asteraceae family endemic to the western and southern coastal region of South 1 Janneke M. Nortje1 Africa. The plant was described in this journal by Laidler in 1928 as ‘D/nhora buchu’, and is one of the Alvaro M. Viljoen3 important types of buchu used by the Nama people. We report the traditional medicinal uses among San Ben-Erik Van Wyk1 and Nama people, based on our interviews with rural participants. These include the treatment of colds, influenza, chest ailments and tuberculosis, as well as convulsions, haemorrhoids and inflammation of AFFILIATIONS: the neck. The major and minor chemical compounds of the essential oil that is produced by the plant are 1Department of Botany and Plant identified, together with the site of accumulation of this volatile oil within the leaf. We also investigated the Biotechnology, University of plant’s antimicrobial activity against a selection of a yeast and two Gram-negative and one Gram-positive Johannesburg, Johannesburg, bacteria, all of which are associated with respiratory infections. P. camphorata is scientifically poorly South Africa known but is an important San and Nama traditional remedy. Our study not only prevents the potential loss 2Department of Pharmacy and Pharmacology, University of the of historically important indigenous knowledge, but also provides the first scientific evidence to validate Witwatersrand, Johannesburg, the traditional use of ǀnhora against upper and lower respiratory tract infections, including tuberculosis.
    [Show full text]
  • Opening the Curiosity Box
    Opening the curiosity box: Botanical images as sites of transformation for the scientific practices of annotation and display in the seventeenth and eighteenth centuries Karen Stewart Thesis presented in partial fulfilment of the requirement for the degree of Masters of Philosophy, Visual Arts (Illustration) at Stellenbosch University Supervisor: Professor Keith Dietrich MARCH 2007 Stellenbosch University https://scholar.sun.ac.za Declaration: I, the undersigned declare that the work contained in this thesis is my own original work and that I have not previously in its entirety or in part submitted it at any university for a degree. Stellenbosch University https://scholar.sun.ac.za Summary This thesis investigates the hidden narratives of South African botanical images made in the late seventeenth to eighteenth century. Plant collecting and image making was part of early modernist scientific practice of collection and display. These images are examined from postmodern perspectives that treat them as "texts" that validated colonial botanical agendas. Botanical art objectified "nature" enforcing it into a textual code that sanitised it and made it suitable for study by Eurocentric natural philosophers. The impact of particular scientific agendas about "nature" can be linked to the stereotyping and subjugation of both indigenous knowledge systems and women. This thesis considers the impact that the complex historical and socio-political situations of the seventeenth and eighteenth centuries had to bear on the discursive formations associated with the botanical sciences, of which botanical art forms an integral part. The process whereby indigenous knowledge was effectively written out of acceptable botanical practice (a trend that persists today) is evaluated.
    [Show full text]
  • Phylogeny of Hinterhubera, Novenia and Related
    Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 2006 Phylogeny of Hinterhubera, Novenia and related genera based on the nuclear ribosomal (nr) DNA sequence data (Asteraceae: Astereae) Vesna Karaman Louisiana State University and Agricultural and Mechanical College, [email protected] Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Recommended Citation Karaman, Vesna, "Phylogeny of Hinterhubera, Novenia and related genera based on the nuclear ribosomal (nr) DNA sequence data (Asteraceae: Astereae)" (2006). LSU Doctoral Dissertations. 2200. https://digitalcommons.lsu.edu/gradschool_dissertations/2200 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. PHYLOGENY OF HINTERHUBERA, NOVENIA AND RELATED GENERA BASED ON THE NUCLEAR RIBOSOMAL (nr) DNA SEQUENCE DATA (ASTERACEAE: ASTEREAE) A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Biological Sciences by Vesna Karaman B.S., University of Kiril and Metodij, 1992 M.S., University of Belgrade, 1997 May 2006 "Treat the earth well: it was not given to you by your parents, it was loaned to you by your children. We do not inherit the Earth from our Ancestors, we borrow it from our Children." Ancient Indian Proverb ii ACKNOWLEDGMENTS I am indebted to many people who have contributed to the work of this dissertation.
    [Show full text]
  • Vegetation of Akkerendam Nature Reserve, Northern Cape: Delineation and Dynamics Over 100 Years
    Bothalia - African Biodiversity & Conservation ISSN: (Online) 2311-9284, (Print) 0006-8241 Page 1 of 9 Original Research Vegetation of Akkerendam Nature Reserve, Northern Cape: Delineation and dynamics over 100 years Authors: Background: Akkerendam Nature Reserve is the second oldest proclaimed municipal nature 1,2 Helga van der Merwe reserve in the Northern Cape, yet to date no vegetation map has been produced. The possible M. Timm Hoffman3 expansion of the reserve is under consideration. Affiliations: 1South African Environmental Objectives: To produce a vegetation map, classification and description of the vegetation of Observation Network the reserve and proposed expansion area, and assess how the vegetation has changed over the (SAEON), Arid Lands Node, past century. Calvinia, South Africa Method: Braun Blanquet methodology was used to produce a vegetation map. To quantify 2Department of Biological vegetation change, (1) relevés (a plot of phytosociological data) composed from Acocks’ Sciences, University of species lists, recorded in 1954 and 1956, were compared with the phytosociological table, Cape Town, Cape Town, South Africa and (2) recent repeat photographs (2016) were compared to four images taken by Pole Evans (ca. 1920). 3Plant Conservation Unit, Department of Biological Results: Three plant communities were identified within the reserve and expansion area; Sciences, University of however, four subcommunities are only found in the proposed expansion area. Relevés Cape Town, Cape Town, compiled from Acocks’ species lists were absorbed into the phytosociological table indicating South Africa that no significant vegetation change has taken place in the last approximately 60 years. This Corresponding author: study found 222 species in common with Acocks’ species lists; however, he did not list the Helga van der Merwe, alien invasive species Prosopis glandulosa.
    [Show full text]
  • Patterns of Plant Diversity in the Hantam-Tanqua-Roggeveld Subregion of the Succulent Karoo, South Africa
    Patterns of plant diversity in the Hantam-Tanqua-Roggeveld Subregion of the Succulent Karoo, South Africa by Helga van der Merwe Submitted in partial fulfilment of the requirements for the degree Philosophiae Doctor in the Faculty of Natural and Agricultural Science Department of Plant Science University of Pretoria Pretoria Supervisor: Prof. M.W. van Rooyen July 2009 © University of Pretoria I hitched my wagon to a daisy Direction vague and destination hazy But, Could any other star have guided me more exactly to where I most dearly loved to be? - Cythna Letty ii Table of contents Abstract ………………………………………………………………............... vii Chapter 1: General introduction …………………………………………… 1 References ……………………………………………………………………… 5 Chapter 2: Study area ……………………………………………….…….. 9 2.1 Location and topography ………………………………………………… 9 2.2 Geology and soils …………………………………………………………. 10 2.3 Climate …………………………………………………………………….... 14 2.4 Vegetation ………………………………………………………………….. 17 2.4.1 Succulent Karoo Biome ………………………………………. 17 2.4.2 Fynbos Biome …………………………………………………... 18 2.4.3 Phytogeographical affinities ………………………………….. 18 2.4.4 Vegetation classification ………………………………..……… 21 References ……………………………………………………………………... 21 Chapter 3: Materials and methods ………………………………..………. 25 3.1 Introduction ……………………………………………………………..…. 25 3.2 Vegetation mapping of the Hantam-Tanqua-Roggeveld subregion ……………………………………………………………………..… 25 3.3 Plant diversity studies …………………………….………………….…. 26 3.3.1 Species-area relationships …………………………………….. 27 3.3.2 Diversity parameters …………………………………………… 28 3.3.3 Life form spectra ………………………………………………… 29 3.4 Life form and species diversity on abandoned croplands in the Roggeveld ………………………………………………………..…….. 29 3.5 Vegetation trends following fire in the Roggeveld ……………..….. 30 References ………………………………………………………………….….. 32 Chapter 4: Vegetation of the Hantam-Tanqua-Roggeveld subregion, South Africa. Part 1. Fynbos Biome related vegetation (VAN DER MERWE, H., VAN ROOYEN, M.W. AND VAN ROOYEN, N. 2008a.
    [Show full text]
  • Phylogeny of Ericameria, Chrysothamnus and Related Genera (Asteraceae : Astereae) Based on Nuclear Ribosomal DNA Sequence Data Roland P
    Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 2002 Phylogeny of Ericameria, Chrysothamnus and related genera (Asteraceae : Astereae) based on nuclear ribosomal DNA sequence data Roland P. Roberts Louisiana State University and Agricultural and Mechanical College, [email protected] Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Recommended Citation Roberts, Roland P., "Phylogeny of Ericameria, Chrysothamnus and related genera (Asteraceae : Astereae) based on nuclear ribosomal DNA sequence data" (2002). LSU Doctoral Dissertations. 3881. https://digitalcommons.lsu.edu/gradschool_dissertations/3881 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. PHYLOGENY OF ERICAMERIA, CHRYSOTHAMNUS AND RELATED GENERA (ASTERACEAE: ASTEREAE) BASED ON NUCLEAR RIBOSOMAL DNA SEQUENCE DATA A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy In The Department of Biological Sciences by Roland P. Roberts B.S.Ed., Southwest Texas State University, 1991 M.S., Southwest Texas State University, 1996 December, 2002 DEDICATION I dedicate this dissertation to my son Roland H. Roberts, my mother Rosetta Roberts and my niece Colleen Roberts, for being a continued source of mutual love and respect. ii ACKNOWLEDGMENTS This dissertation was developed under the direction of my advisor, Dr. Lowell E. Urbatsch, Director of the Louisiana State University Herbarium and Associate Professor in the Department of Biological Sciences.
    [Show full text]
  • A Taxonomic Revision of the Pteronia Camphorate Group (Astereae, Asteraceae)
    Bello, A.O. et al. (2017). A taxonomic revision of the Pteronia camphorate group (Astereae, Asteraceae). South African Journal of Botany, 113: 277-278 https://dx.doi.org/10.1016/j.sajb.2017.08.017 A taxonomic revision of the Pteronia camphorate group (Astereae, Asteraceae) A.O. Bello, J.S. Boatwright, P.M. Tilney, M. Van der Bank and A.R.Magee Abstract: As a first step towards a comprehensive revision of Pteronia (Asteraceae, Astereae), we present here a taxonomic treatment of the Pteronia camphorata group, in which we recognise three species. The group includes the type spe- cies P. camphorata (an important medicinal plant) and is easily distinguished from the rest of the genus by the gla- brous rather than glandular or variously pilose cypselas. The lectotype of P. camphorata has involucral bracts with entire margins and long acuminate apices, both diagnostic characters for P. stricta. As such P. stricta is here reduced into synonymy with P. camphorata and the next available name, P. aspera Thunb, reinstated to accommodate the species heretofore treated as P. camphorata. Three varieties within Pteronia camphorata had been previously recognised (var. armata, var. laevigata and var. longifolia). The characters distinguishing var. armata were found to be continuous with the variation observed within var. longifolia. The third infraspecific taxon, var. laevigata, was however found to be distinct and is therefore recognised here as a new species, P. cederbergensis Bello, Magee & Boatwr. It is readily distinguished by the glabrous branches, opposite to sub-opposite somewhat succulent leaves, the 2-seriate pappus and larger, obclavate cypselas. Transverse sections of the leaves and cypselas were also examined and provide additional differences between the three recognised species.
    [Show full text]
  • Restoration Potential of Invaded Abandoned Agricultural Fields: What Does the Seed Bank Tell
    Restoration Potential of Invaded Abandoned Agricultural Fields: What Does the Seed Bank Tell Us? Running head: Seed bank contribution to rangeland restoration Natalie S. Haussmanna*, Christopher Delporta, Vincent Kakembob, Katlego K. Mashianea, Peter C. le Rouxc a Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa b Geosciences Department, Nelson Mandela University, PO Box 77000, Port Elizabeth, 6031, South Africa c Department of Plant and Soil Sciences, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa *Corresponding author: e-mail: [email protected] Author contributions: NH, CD, KM, PLR, VK conceived and designed the research; CD, KM performed the fieldwork and experiments; PLR analyzed the data; NH, PLR, VK wrote and edited the manuscript 1 Abstract Soil seed banks can play an important role in the restoration of degraded ecosystems, especially where indigenous species are well represented in, and invasive species are largely absent from the seed bank. Here, we studied the potential contribution of the soil seed bank to the restoration of invaded, abandoned agricultural fields in the Eastern Cape, South Africa. We recorded the aboveground cover and belowground abundance of all vascular plant species from 120 quadrats that differ in cover of the extralimital woody invader, Pteronia incana. Our results show that higher cover of P. incana is associated with lower species richness, aboveground cover and belowground seed abundance. Furthermore, community similarity between the above- and belowground component was low, with the seed bank and standing vegetation having only 15 species in common and 49 species being recorded only from the seed bank.
    [Show full text]
  • Variation in the Essential Oil Constituents of Pteronia Incana (Asteraceae)
    African Journal of Biotechnology Vol. 5 (12), pp. 1220-1226, 16 June 2006 Available online at http://www.academicjournals.org/AJB ISSN 1684–5315 © 2006 Academic Journals Full Length Research Paper Variation in the essential oil constituents of Pteronia incana (Asteraceae) B. Mayekiso1, M.L Magwa2 and R.M Coopoosamy1* 1Department of Botany, 2Electron Microscopic Unit, University of Fort Hare, Private Bag X1314, ALICE, 5700, Eastern Cape, SOUTH AFRICA Accepted 10 May, 2006 The essential oil of Pteronia incana was collected and was investigated on a monthly basis using GC- MS. The oil volume and its constituents vary greatly with different time of sampling and distillation. The oil contains a high percentage of myrcene α-pinene, β-pinene with sabinene, α-terpinene, 1.8 cineole and limonene. Key word: Pteronia incana, Asteracea, essential oil. INTRODUCTION Pteronia incana belonging to the Asteraceae family has interest was to investigate the quantity, quality and been regarded as a weed in the Eastern Cape, Republic variation of the oil on monthly bases and try to compare of South Africa (Webber et al., 1999). The plant cover its constituents. This will enhance which month is the approximately 60 000 hectares of land and is also best for harvesting this plant either for commercial or regarded as unpalatable to livestock by the farmers in the research purposes. region. Scientifically it has been demonstrated that plants produce secondary metabolites for defense purposes (Wink 2003; Koschier et al., 2002; Werker et al., 1993; MATERIALS AND METHODS Duke, 1993; Wagner, 1991; Bell, 1981; Reynolds and Rodriguez, 1984; Croteau, 1977).
    [Show full text]
  • The Invasion of Pteronia Incana (Blue Bush) Along a Range of Gradients In
    The invasion of Pteronia incana (Blue bush) along a range of gradients in the Eastern Cape Province: It’s spectral characteristics and implications for soil moisture flux JOHN ODHIAMBO ODINDI Submitted in fulfilment of the requirement for the degree of PHILOSOPHIAE DOCTOR in the Faculty of Science at the Nelson Mandela Metropolitan University January 2009 Promoter: Professor Vincent Kakembo i Abstract Extensive areas of the Eastern Cape Province have been invaded by Pteronia incana (Blue bush), a non-palatable patchy invader shrub that is associated with soil degradation. This study sought to establish the relationship between the invasion and a range of eco-physical and land use gradients. The impact of the invader on soil moisture flux was investigated by comparing soil moisture variations under grass, bare and P. incana invaded surfaces. Field based and laboratory spectroscopy was used to validate P. incana spectral characteristics identified from multi-temporal High Resolution Imagery (HRI). A belt transect was surveyed to gain an understanding of the occurrence of the invasion across land use, isohyetic, geologic, vegetation, pedologic and altitudinal gradients. Soil moisture sensors were calibrated and installed under the respective surfaces in order to determine soil moisture trends over a period of six months. To classify the surfaces using HRI, the pixel and sub-pixel based Perpendicular Vegetation Index (PVI) and Spectral Mixture Analysis (SMA) respectively were used. There was no clear trend established between the underlying geology and P. incana invasion. Land disturbance in general was strongly associated with the invasion, as the endemic zone for the invasion mainly comprised abandoned cultivated and overgrazed land.
    [Show full text]